1. Field of the Invention
The invention relates generally to building systems, and more particularly, to an improved apparatus and method for forming a framed opening in a poured concrete wall made with insulated concrete forms, for example, that remain a permanent part of the wall.
2. Discussion of the Related Art
Conventional building construction utilizes concrete foundation walls which are normally produced by constructing form walls, pouring concrete into the space between the walls and, upon setting of the concrete, removing the form walls. Finishing materials are then added to the concrete foundation walls as required. Framing members, often made of wood, will then be constructed on top of the foundation walls. Insulation may then be inserted between the framing members and the wall finished inside and out as desired.
More recent building systems involve the use of insulated concrete forms (ICF""s) which comprise a foam insulating material to construct permanent concrete form walls. The form walls are constructed by placing separate building components upon each other. The concrete is then poured and the form walls are left in place, even after the concrete hardens. The concrete wall so formed need not be confined to foundation walls but may comprise all of a building""s walls. Generally, no further insulation is necessary, and known finishing materials of all types, including veneer finishes, stucco, gypsum boards, etc., may be applied to the interior and exterior of the wall as required. An example of a particularly advantageous type of ICF appears in U.S. Pat. No. 5,390,459 (Mensen) and U.S. Pat. No. 5,657,600 (Mensen), the disclosures of which are incorporated by reference herein in their entirety. As shown in FIG. 1, the ICF""s of these patents are made from a building component 10, which includes first and second high density foam sidepanels 12 and 14. The sidepanels 12 and 14 are preferably made of expanded polystyrene and are arranged in spaced parallel relationship with their inner surfaces facing each other. Plastic bridging members 42 molded into the sidepanels hold them together against the forces applied by the poured concrete. Each bridging member includes end plates 44, 46, which line up when the components are stacked to form furring strips for attachment of finishing materials. As these building components 10 are stacked to become an ICF form wall, it becomes necessary to provide block-out systems known in the art as xe2x80x9cbucksxe2x80x9d to provide openings for installing components, such as windows or doors, within the ICF form wall.
In conventional, pre-ICF, concrete building systems discussed above, wood or metal bucks have been utilized to provide such a block-out opening in the wall. Many of these conventional bucks are removable once the concrete has hardened, similar to the wood forms used in these pre-ICF building systems, and are referred to within the construction art as xe2x80x9creusable bucksxe2x80x9d. Examples of reusable buck systems are disclosed in U.S. Pat. No. 2,787,820 (Shields et al.) as well as in U.S. Pat. No. 5,169,544 (Stanfill et al.).
With the advent of the use of stay-in-place forms or permanent concrete formwork, such as ICF""s, the current practice has been to build a wooden framed buck to provide an opening in the wall for installing a component, such as a window or a door. This frame is typically constructed from standard-sized lumber such as 2xe2x80x3xc3x9712xe2x80x3 or 1xe2x80x3xc3x9712xe2x80x3. If left in place after the poured concrete has cured, this wooden frame of the buck provides a fastening surface for the window or door and its finishing trim.
An example of such a known window buck in an ICF wall is denoted generally as 23 in FIG. 2, which shows the use of, for example, 2xe2x80x3xc3x9712xe2x80x3 lumber 25 to create the top and sides of the buck. The wooden buck retains the concrete and also provides solid attachment surfaces for interior and exterior finishes around the edge of the openings. The bottom 27 of the buck frame may be created with two 2xe2x80x3xc3x974xe2x80x3""s in an arrangement which will provide a slot to allow proper placement and consolidation of concrete below the opening. In order to keep the wood frame properly aligned in the opening within the stacked wall forms, 1xe2x80x3xc3x974xe2x80x3 wood strapping 29 may be fastened to the perimeter facings of the frame as shown in FIG. 2. This will ensure alignment of the wall forms with the wood frame. The 1xe2x80x3xc3x974xe2x80x3 strapping 29 may be removed and reused once the concrete has set.
When the wooden buck frame is to be left in the wall, it must be firmly secured to the concrete. The frame may be fastened to the concrete by using fasteners, such as nails or anchor bolts, secured to the frame and left hanging between the sidepanels of the ICF system. The subsequent pouring of wet concrete between the two sidepanels will cause the wet concrete to flow around the fastener and thus aid in holding the frame in place once the concrete has hardened.
The opening formed by a wood buck for a window and door opening typically require supplemental bracing inside the frame to prevent deflection of the wood members under pressure from the poured concrete. This can be accomplished, for example, by placing one or more pieces of lumber in the opening to brace from side to side and/or from top to bottom. Other bracing arrangements commonly used in the building construction arena utilize dimensional lumber (i.e. 2xe2x80x3xc3x974xe2x80x3, 2xe2x80x3xc3x976xe2x80x3, or 2xe2x80x3xc3x978xe2x80x3, for example). Fiber tape has also been utilized to secure, or assist in securing, the attachment of the buck to the form while the concrete is setting.
The wooden construction of these conventional bucks results in a variety of problems because of the inherent qualities of wood. For example, wood may change dimensions over time as a result of variations in humidity and temperature. This results in a common problem known in the construction field as buck shrinkage, which can affect the thermal performance of the wall and the attached component. If the conventional buck frame members undergo buck shrinkage, they may cup, warp and/or twist. This frequently results in cracks in the wall providing opportunities for air infiltration thereby compromising the thermal performance of the walls. Moreover, the use of wooden framed bucks may lead to significant problems resulting from insect infestation. Also, the wood frame has low thermal insulative properties, which is becoming an increasingly significant issue in modem construction.
Current stay-in-place bucks, such as that shown in FIG. 2, use fasteners such as nails or screws to attach the window, door, or other component to be mounted within the opening to the buck. The fasteners connect the mounted component to the buck and are anchored either within the wooden buck frame itself or within the adjacent concrete of the building wall. While such an attachment method is feasible, it is often difficult to anchor fasteners within the hardened concrete of the building wall. Moreover, the inherent dimensional instability and other detrimental qualities of wood, including those discussed above, can result in undependable alignment of the mounted component within the form wall system, as well as cracking of interior wall finishing, such as dry wall. Moreover, the cost of constructing such wooden retainers in terms of material and labor is high, especially when constructing a large commercial building, or other structure with many wall openings.
As a result of the foregoing problems and disadvantages, there is a need in the building construction art for a more efficient, cost-effective and reliable apparatus and method for forming a framed opening in a poured concrete wall made with permanent concrete formwork, such as ICFs, which will provide dependable containment of wet concrete within the wall during curing, improve the structural stability of the overall building wall system, facilitate the attachment of components, such as windows and doors, within the wall opening, and overcome the problems inherent with currently used wood block-out wall opening systems.
The invention solves these problems and avoids the drawbacks and disadvantages of the prior art by providing a buck formed of insulating material compatible with the concrete form, such as plastic, that forms a friction fit with supporting portions of an insulated concrete form wall. As a result, the buck is more stable during construction and better able to dependably contain wet concrete within the wall during curing than prior art bucks. The buck of the invention may have a portion for receiving fasteners to secure a component mounted on the buck, thus facilitating the attachment of components to the buck within the wall opening, and reducing or completely eliminating the need for fasteners to penetrate hardened concrete. The buck may also include a separate portion, preferably integrated with the fastening portion, that provides for enhanced thermal insulation. The buck may also include anchoring fins around which the poured concrete may harden and securely and sealingly attach the buck to the form.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described and according to a first aspect of the invention, a buck is provided for forming and framing the perimeter of an opening in an insulated concrete form wall and attaching a component mounted in the opening to the wall. This buck includes first and second portions configured to engage spaced portions of an insulated concrete form wall forming the perimeter of the opening; a fastening section for attaching a component to the buck; and an insulating section.
The fastening and insulating sections may be formed by a plurality of air chambers defined by walls of a multi-layer structure, which receive and retain fasteners, preferably entirely within the chambers to avoid having to penetrate the hardened concrete. An anchoring portion, such as a T-shaped fin, may be provided to hold the buck in the concrete and, with the frictional engagement of the buck and the ICF, sealingly attach the buck and the ICF together. Preferably, the buck is formed from plastic material and includes ribs and/or score lines for facilitating construction by increasing friction between the buck and component to be mounted and/or providing indicia locating placement of fasteners and/or cutting lines to remove a portion of the buck when certain types of finishing materials, like stucco, are to be applied. With the buck of the invention, the component may be center or flange (side) mounted within the opening, as with conventional wood bucks.
In a further aspect of the invention, a method of making framed openings in a poured concrete wall made with permanent concrete formwork, is provided. This method includes the steps of constructing permanent concrete formwork having an opening; providing plastic bucks having at least one insulating chamber; frictionally attaching the bucks to the perimeter of the concrete formwork forming the opening; and pouring concrete into the formwork. A window, door, or other wall component may be directly mounted to the buck by fasteners, preferably received entirely within the buck. The bucks may include insulating air chambers within which the fasteners are received. Also, a finishing material may be directly attached to the buck.
Additional features and advantages of the invention will be set forth or be apparent from the description that follows. The features and advantages of the invention will be realized and attained by the structures and methods particularly pointed out in the written description and claims hereof as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide explanation and context for the invention, the scope of which is limited solely by the appended claims.